Sahih al-Bukhari Book 34, Hadith 1

You people say that Abu Huraira tells many narrations from Allah's Messenger (ﷺ) and you also wonder why the emigrants and Ansar do not narrate from Allah's Messenger (ﷺ) as Abu Huraira does. My emigrant brothers were busy in the market while I used to stick to Allah's Messenger (ﷺ) content with what fills my stomach; so I used to be present when they were absent and I used to remember when they used to forget, and my Ansari brothers used to be busy with their properties and I was one of the poor men of Suffa. I used to remember the narrations when they used to forget. No doubt, Allah's Messenger (ﷺ) once said, "Whoever spreads his garment till I have finished my present speech and then gathers it to himself, will remember whatever I will say." So, I spread my colored garment which I was wearing till Allah's Messenger (ﷺ) had finished his saying, and then I gathered it to my chest. So, I did not forget any of that narrations.